I. Cross-Reference to Related Applications
Cross reference is made to related applications Ser. No. 08/001995 to Mario DiMarco, a co-inventor in the present application, entitled "ELECTRICAL CONNECTOR INCORPORATING GROUND SHIELD SPACER" and 08/002296, to Timothy J. Wilhelm , a co-inventor in the present application, entitled "MULTI-COPLANAR CAPACITOR FOR ELECTRICAL CONNECTOR", both filed of even date and assigned to the same assignee as the present application.
II. Field of the Invention
This invention relates generally to electrical connectors for connecting electrical devices or parts to a cable harness, and more particularly to a connector assembly incorporating an input/output core filtering system to improve the isolation of the electrical assembly with which the connector is used from electromagnetic interference (EMI), radio frequency interference (RFI), and particularly HF, VHF and UHF radio frequencies.
III. Discussion of the Prior Art
Present-day commercial and military aircraft incorporate highly complex electronic control systems incorporating numerous sensors and force transducers and servo systems as well as the electronics necessary for processing the sensor signals and developing the requisite control signals for the transducers and the like so that the aircraft can be flown in a controlled manner. Typically, the electronic assemblies involved will be housed in metallic shielding enclosures or boxes which are adapted to slide into equipment racks on the aircraft. Each of the electronic modules will typically incorporate a receptacle having a large number of terminal pins arranged in a grid pattern and which are appropriately wired to the electronic componentry within the shielded enclosure. Incorporated into the rack assembly is a plug member which is adapted to mate with the receptacle on the box housing the electronics module. The pins of the plug are typically connected to conductors in a wiring harness leading off to other electronic equipment which may be spread throughout the aircraft.
One standard plug used throughout the aircraft industry is referred to as the ARINC 600 plug, which meets the ARINC specifications for air transport avionics equipment interfaces. That specification, among other things, defines the number of pins, their location, the pin spacing and the shell dimensions for the plug. Those desiring more specific information relative to the plug are referred to the ARINC 600 specification itself.
The ARINC 600 plug is designed to mate with a receptacle attached to or formed into a wall of the shielding enclosure in which the electronics are contained. The ARINC 600 plug includes three sections with sections A and B incorporating 150 male pins, each disposed in a grid array of rows and columns. Section C includes a smaller number of pins which, generally speaking, provide the power connections to the electronics module. The existing receptacle, designed to accept the plug, includes a plurality of terminal pins having female sockets on one end and male wire wrap terminals or solder points on the other end. The pins are arranged in the same grid array, such that when the plug is inserted into the receptacle, the male pins of the plug engage the female sockets of the receptacle's terminal pins. The male portion of the receptacle's terminal pins then connect to the wiring for the electronics within the shielded enclosure.
One drawback of the prior art ARINC 600 connector design is that it does not provide the necessary immunity of the electronic circuitry from the effects of EMI and more particularly filter out HF, VHF and UHF frequency ranges. EMI radiation in proximity to the module may find its way into the interior of the shielded enclosure via the connector assembly. These EMI sources may result in the electronic controls issuing erroneous data to the other electronic equipment with which it is associated, resulting in loss of control over the aircraft.
While filtering and transient suppression circuits have been devised for dealing with EMI radiation, physical space constraints may preclude inclusion of such circuitry within the electronics module. A need, therefore, exists for a connector plug receptacle assembly which has an efficient high energy ground associated with a shield or filtering device which combines an efficient shield for the EMI/RFI frequencies of interest with an excellent chassis ground.